Following in the footsteps of the early UNIX game Robots (and perhaps from there the still-earlier BASIC game Chase?), this game puts the player in charge of a little protagonist, often claimed to be The Doctor, occupying a position on a top-down grid which is otherwise strewn, not with mines, but with those killer cyborgs which are his personal nemesis, the Daleks. They have no long-range weapons, but if they touch him, he will find himself ex-ter-min-ated!
Fortunately for him, contact with them is as lethal to each other as it is to him. Every time he takes a step, they all draw one square closer to him; The Doctor's cunning strategy is to manoeuvre himself so as to cause their paths to intersect and the Daleks to terminally collide, leaving a pile of rubble dangerous both to him and to subsequent Daleks -- a strategy not always possible on the narrow confines of a grid. Fortunately for the good Doctor, where this game outdoes its predecessors is that he also has his trusty Sonic Screwdriver in hand, whose offensive use destroys all Daleks within a threatening one-square radius of him. Also, it allows him to teleport out of harm's way to a random location on the map -- hopefully one behind a pile of Dalek rubble, and not one within a single step of a Dalek currently on the map. In many versions both Sonic Screwdriver and Teleport use are limited. Should The Doctor survive this onslaught, he is brought to a new grid map, generally one populated with still further Daleks.
Other features particular to some versions and absent from others include the use of graphical tiles vs. mere roguelike textmode character representation, and occasionally a conversion will use (universally unlicensed) sound effects taken from canonical Doctor Who sources; more commonly these games also offer a Last Stand command, to be used, like the "drop" in Tetris, when the player is so confident in the security of their location that they are willing to sit tight and grant the Daleks as many moves as it takes to either reach The Doctor or be rendered down into scrap metal through unforeseen collision. Successful use of the Last Stand often results in a score bonus; unsuccessful use of it, of course, results in The Doctor's death. (Don't worry, chances are good that he'll regenerate into a new incarnation -- not in this game, however).
Some versions feature keyboard directional control (in which sometimes the player is granted access to diagonal movement like the Daleks are, and sometimes not), while others present The Doctor with a halo of directional arrows around him, to move him one step in the appropriate direction if an arrow is clicked upon. Generally he also has the option of standing in place and passing a turn.